Hydraulic dredging machine



June 10, 1952 H. K. DUNNlNG HYDRAULIC DREDGING MACHINE 2 SHEETS SHEET 1 Filed Jan. 25, 1947 INVENTOR. HOMER K. DUNN/N6 ATTORNEY June 10, 1952 H. K. DUNNING HYDRAULIC DREDGING MACHINE 2 SHEETS SHEET 2 Filed Jan. 25, 1947 INVENTOR. HOMER K DUNN/N6 ATTOENEY Patented June 10, 1952 Homer K. Dunniug,. San Francisco, (la-fill, as signor of one-halfatoeoscar Thomas 'McShane,

.San Eraneiscm-Galif.

ApplicationjJanuai y 25, 1947, Serial No. 724,279 .s-elaims. (01.1375 2) The present invention relates to-i-mprovements inhyd-raulic dredging machines and its principal object is to provide a convenient machine for dredging alluvial deposits from submerged surfaces,-as from the bottomof a pond, lake, river or the like.

It is particularly proposd for this purpose to utilize suction means for elevating and'discharging deposits from the bottom of a submerged area in a-continuous stream.

It is further proposed to utilize-a jet of water discharged into the submerged lower portion of a tube in an upward direction for entraining water and solids-from the-submerged area-for discharge through-the upper end of the'tube.

It is a further object oi -the invention-to provide means for simultaneouslydisintegrating the alluvial deposits of the 'submerged area underneath the tube and tocreate a turbulent condition in the affected area whereby the solids are held in suspension and aremore readily-entrained in the water sucked through the tube.

It is particularly proposd to utilize forthis purpinging "upon the submerged earth deposits whereby the latter are disintegrated and --mixed with the water in the area subject to the draft of the tube.

And finally, itis'proposed to providemeansin connection with the discharge end of the tube for arranging a discharge chute and for compensating for the rising and lowering of the tube to provide a substantially constant pressure head for different positions of the tube.

Further objects and advantages of my invention will appear as'the specification proceeds, and the novel features ofmy invention will be fully defined inthe claims attached hereto.

The preferred form of my invention *is illustrated in the accompanying drawing, inwhich:

Figure '1 shows a vertical section through my hydraulic dredging-machine, certain portions being broken away;

Figure 2, a side elevation of the same on a reduced scale;

Figure 3, ahorilzontal section taken along-line 3-3 of Figurel;

Figure 4, a horizontal section taken along'line 4-4 of Figure 1;

Figure 5, a horizontal section taken along line 5-5 of Figure 1; and

Figure 6,,a-bottom plan view of the machine.

WhileT have shown only the preferred form of my-invention, I wish to have it understood that various'changes' and'modificationsmaybe made within the: scope of .thenlaims at ached hereto without. departing from the spirit of the invention.

Referringitothe drawings detail, my invention comprises in its principal features an inner tube 1-, an outer tube; 2 anda discharge head 3 having a dischargexchute 4 Theinner tube 1 is here- -shown as being made of several sections 5, .6' and J, the-intermedi te section 6 being interposed between the "two other tight connection between the head. 3 and the upper tube section.

'Inthe .usual arrangement of the ;n 1 achi ne,- the head :3 may be considered .as being mounted at a fixed..-elevation but with freedom of movement in a horizontal plane as,,for instance, at the upper end .of the boom of ,a dred er, while the inner tube is mounted with freedom of vertical sliding movement with respect to the-header) that the tube may .be raised and lowered for bringing the bottom end thereof into {a desired position with respect to the bottom of- :the pond .or lake in which the .dredger operates.

The lower end of the inner tube section ,5 terminates in an enlarged bell-shaped mouth I!) joined to the tube through ,azconical section. H as shown.

. A cylindrical chamber [2; is mounted concentrically inside of the mouth I0 01'. the inner tube and is provided with removable and replaceable nozzles l3 and HI, both being axially located, and the nozzle l3 pointing upward while the nozzle l4 points downward. The chamber is supported in part by 4 evenly spaced radial flues 15' which establish connection between. the chamber and an outer passage I6 formed by the inner tube l and the outer tube 2. The lower end of this passage is closed, as shown at IT, so that when water under pressure is pumped through branch pipes 18 the water is forced downthe annular passage l6 and through the flues l5--into the chamber 12 for discharge through the-nozzles 4 3 and M.

The fiues l5 constitute natural barriers: for water rising through the-space between the chamher -I 2 and the mouth of the innertuba'but it is desirable to exactly control the-area. available-tor the rising water with respect to the tube area, and in order to properly proportion the space allowed for the rising water I provide a cylindrical housing l9 around the chamber, the housing terminating in a tapered portion 20 at the upper end, substantially at the elevation of the tapered section I I of the inner tube.

The annular space thus formed between the housing l9 and the inner tube is further reduced by providing partitions 21 on opposite sides of each flue l5, the partitions at each flue being lift required by the raising of the tube within the head.

Thus the static pressure, that is, the pressure required for lifting the water and the solids from the level of the pond to the upper end of the tube, remains substantially constant for difierent positions of the tube.

The bottom H of the passage 16 is preferably providedwith a plurality of downwardly projecting nozzles 21 which are used for auxiliary disintegrating jets, and additional inclined nozzles joined by top members 22 and bottom members 7 23. Due to this construction only 4 passages 24 are left for the rising water, and the total crosssectional area of these 4 passages should bear a definite relation to the cross-sectional area of the inner tube l. p

In establishing this relationship the object to be aimed at is to provide uniform speed for the rising water, and I find that this condition is substantially met by making the total area of the 4 passages 24 approximately three-fourths of that of the tube l, allowing one-fourth of the area of the tube to be taken up by the jet emanating from the nozzle l 3.

The upper section l of the tube 1 is slidable in the bottom ofthe head 3 and the tube may be operated for raising and lowering the same in any suitable manner (-not shown). For operating, the mouth ofthetube is immersed into the body of water so as to bring the open end within operative proximity of the underlying bottom. Through suitable hose connections, not shown, water is pumped under pressure, into the branches 18, which serve to balance one another, and passes through the annular passage N5, the flues l5 and the chamber [2 into the nozzles l3 and M to be discharged from the latter at high velocity. The jet emanating from the lower nozzle l4 impinges upon the bottom of the pond, disintegrates the bottom material and sets up a general turbulence, causing the solids to rise and disperse through the water in the'area underneath the mouth of the tube.

At the same time, water discharging through the upper nozzle l3 creates suction in the tube and entrains water and water-carried solids from underneath the mouth of the tube, the water and solidsbeing discharged over the upper edge of the tube and upon the chute 41, which latter again discharges upon a suitable launder, not shown.

, Since the tube I can be adjusted to various different heights, it is apparent that the working head, that is the distance between the water level and the upper end of the tube, varies with different positions of the tube. It is lowest when the tube is in its lowermost position, that is, with its upper end approximately opposite the bottom of the chute, and highest when the tube is in its uppermost working position, approximately as shown in the drawing. 1

It is proposed, however, to compensate for these changes in theworking head by making the head 3 in the form of an inverted vessel, closed at its upper end, as shown, and by providinga separat ing disc 25 in the head above the chute, the disc being formed with openings 26 having an aggregate discharge area approximately equal to the cross-sectional area-of the tube l. Due to this construction the water and solids discharged over the upper end of the tube crowd out the air and completely fill the head 3, and descendin on the outside of the tube produce a siphoning action sufiiciently strong to compensate for the extra 28 are arranged in the lower end of the tube mouth, opposite the passages 24 to discharge jets of water across the entrances to the passages for intercepting and driving back solids too large to be accommodated in the passages.

In order to test the efliciency of my machine, and particularly that of the disintegrating jet, I have carried out a number of experiments, using a model made to the dimensions of the drawing, the inner tube 14" long, workingpressure 22 lbs. operating on submerged sea sands, for one hour periods, and arrived at the following figures:

1. Using the elevating jet (nozzle I3) only:

The consumption of the elevating jet, running free, was 1,620.95 lbs. Working on water only, the entrained water amounted to 5,009.5 lbs. Thus the proportion of the water emitted from the jet to the entrained water was 1:3.127, which accounts for the suggestion that thecombined area of the passages 24 should be approximately three-fourths ofthat of the tube, allowing onefourth for the jet.

Working on water and sand, the weight of the entrained sands was 756 lbs. and that of the entrained water 4,253.5, the percentage of solids carried in suspension being 17.75%.

2. Using both jets (nozzles 13 and i4):

The consumption of the lower jet was 635.84 lbs. Working on water only, the weight of the entrained water was 4,383.27 1bs., that is, 626.23 less than in the case where the elevating jet only was used. Working on sand and water, the weight of the entrained sand was 1,080 1bs. and that of the entrained water 3,303.27 lbs. making the percentage of solids carried in suspension Thus the use of the disintegrating jet added 324 lbs. of sand to the discharge and raised the percentage of solids carried in suspension from 17.75% to 32.3%. 1

I'claim; 7

1. In a hydraulic dredging machine of the character described, a tube having a mouth at one end adapted for immersion into a pond or the like, a chamber inside the mouth and having axially disposed nozzles pointing in opposite directions, a second tube surrounding the first tube and the mouth so as to form an annular passage therewith, and conduit connections in the mouth between the passage and the chamber for guiding water under pressure into the latter for discharge through the nozzles, the mouth having an annular series of passages leading from the bottom of the mouth to the tube.

2. In a hydraulic dredging machine of the character described, a tube having a mouth at one end adapted for immersion into a pond or the like, a chamber inside the mouth and having axially disposed nozzles pointing in opposite directions, a second tube surrounding the first tube and the mouth so as to form an annular passage therewith, and conduit connections in the mouth between the passage and the chamber forguidingwater under pressure into the latter for dis- 5 charge through the nozzles, the mouth having an annular series of passages leading from the bottom of the mouth to the tube, the annular passage between the two tubes being closed and having discharge nozzles intersecting the annular series of passages.

3. In a hydraulic dredging machine of the character described, a tube having a mouth at one end adapted for immersion into a pond or the like, a chamber inside the mouth and having axially disposed nozzles pointing in opposite directions,'conduit connections in the mouth between the wall of the latter and the chamber, and means for guiding water under pressure through the conduit connections into the chamber for discharge through the nozzles, the mouth having an annular series of restricted passages leading from the bottom of the mouth to the tube, and the water guiding means having discharge nozzles intersecting the annular series of passages.

4. In a hydraulic dredging machine of the character described, a tube having a mouth at one end adapted for immersion into a pond or the like, a chamber inside the mouth and having axially disposed nozzles pointing in opposite directions, conduit connections in the mouth between the wall of the latter and the chamber, and means for guiding water under pressure through the conduit connections into the chamber for discharge through the nozzles, the conduit connections being arranged radially with respect to the mouth of the tube so as to leave passages between the same, and the water guiding means having discharge nozzles below said passages so as to intersect the latter.

5. In a hydraulic dredging machine, a vessel having a reduced opening in the bottom thereof and having a lateral discharge near the bottom, and a tube having an upper end vertically slidable in the opening and having suction means at its lower end adapted to draw material from below a water level for discharge through the tube into the vessel, the upper end of the vessel being closed to produce a siphon efiect adapted to compensate for a lifting of the tube in the vessel in maintaining a substantially constant pressure head for difierent positions of the tube.

6. In a hydraulic dredging machine, a vessel having a reduced opening in the bottom thereof and having a lateral discharge near the bottom, and a tube having an upper end vertically slidable in the opening and having suction means at its lower end adapted to draw material from below a water level for discharge through the tube into the vessel, the upper end of the vessel being closed to produce a siphon effect adapted to compensate for a lifting of the tube in the vessel in maintaining a substantially constant pressure head for different positions of the tube, and the vessel having a diaphragm stretched across the same immediately above the lateral discharge with a central opening therein through which the tube may pass, the effective area of the diaphragm opening outside the tube being approximately the same as that of the inside of the tube.

HOMER K. DUNNING.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 105,056 Eads July 5, 1870 811,275 Cole Jan. 30, 1906 821,670 Parker May 29, 1906 2,125,740 Schacht Aug. 2, 1938 2,413,561 Hehr Dec. 31, 1946 FOREIGN PATENTS Number Country Date 1,264 Germany Oct. 20, 1877 

